Method and system for cleansing wafer in cmp process of semiconductor manufacturing fabrication

ABSTRACT

A method for cleaning a semiconductor wafer after a Chemical Mechanical Polishing (CMP) process is provided. The method includes providing the semiconductor wafer into a cleaning module. The method further includes cleaning the semiconductor wafer by rotating a cleaning brush assembly. The method also includes applying an agitated cleaning liquid to clean the cleaning brush assembly.

BACKGROUND

Semiconductor devices are used in a variety of electronic applications,such as personal computers, cell phones, digital cameras, and otherelectronic equipment. The semiconductor industry continues to improvethe integration density of various electronic components (e.g.,transistors, diodes, resistors, capacitors, etc.) by continualreductions in minimum feature size, which allows more components to beintegrated into a given area. These smaller electronic components alsorequire smaller packages that utilize less area than the packages of thepast, in some applications.

During the manufacturing of the semiconductor devices, variousprocessing steps are used to fabricate integrated circuits on asemiconductor wafer. Generally, the processes include a chemicalmechanical polishing (CMP) process for planarization of semiconductorwafers. A challenge of the CMP process is to produce a clean substratesurface following the polishing. Therefore, a concern with the use of aCMP process is the efficient and complete removal of the polishingslurry and other polishing residues and particulates following polishingin order to prevent introduction of defects into the polished product.Ideally, post-CMP cleaning should remove all polishing slurry, polishingresidues and particulates in a quick and repeatable fashion withoutintroducing additional defects or damage to the substrate surface.

Although existing methods and devices for cleaning the semiconductorwafer after the CMP process have been generally adequate for theirintended purposes, they have not been entirely satisfactory in allrespects. Consequently, it would be desirable to provide a solution forthe process control for semiconductor manufacturing operations.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It shouldbe noted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a schematic view of a Chemical Mechanical Polishing (CMP)system for processing a semiconductor wafer, in accordance with someembodiments.

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1.

FIG. 3 is a schematic view of a cleaning module, in accordance with someembodiments.

FIG. 4 is a schematic view of a cleaning module, in accordance with someembodiments.

FIG. 5 is a flow chart of methods for processing a semiconductor wafer,in accordance with some embodiments.

FIGS. 6A-6C are cross-sectional views of a scrubber after being used toclean different wafers, in accordance with some embodiments.

FIG. 7 is a cross-sectional view of stage of a process for cleaningsemiconductor wafers in a cleaning module, in accordance with someembodiments.

FIG. 8 is a schematic view of a Chemical Mechanical Polishing (CMP)system for processing a semiconductor wafer, in accordance with someembodiments.

FIG. 9 is a cross-sectional view taken along line B-B of FIG. 8.

FIG. 10 is a schematic view of a cleaning module, in accordance withsome embodiments.

FIG. 11 is a schematic view of a cleaning module, in accordance withsome embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the subject matterprovided. Specific examples of solutions and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Furthermore, spatially relative terms, such as “beneath,” “below,”“lower,” “above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. It is understood thatadditional operations can be provided before, during, and after themethod, and some of the operations described can be replaced oreliminated for other embodiments of the method.

FIG. 1 is a schematic view of a Chemical Mechanical Polishing (CMP)system 1 for processing a semiconductor wafer 5, in accordance with someembodiments. The CMP system 1 includes a CMP module 10, a rinse stationmodule 20, a number of cleaning modules, such as the cleaning modules 30and 40, a spin-rinse-dry (SRD) module 50, and a number of transferringmodules 60. The elements of the CMP system 1 can be added to or omitted,and the disclosure should not be limited by the embodiments.

The semiconductor wafer 5 may be made of silicon or other semiconductormaterials. Alternatively or additionally, the semiconductor wafer 5 mayinclude other elementary semiconductor materials such as germanium (Ge).In some embodiments, the semiconductor wafer 5 is made of a compoundsemiconductor such as silicon carbide (SiC), gallium arsenic (GaAs),indium arsenide (InAs), or indium phosphide (InP). In some embodiments,the semiconductor wafer 5 is made of an alloy semiconductor such assilicon germanium (SiGe), silicon germanium carbide (SiGeC), galliumarsenic phosphide (GaAsP), or gallium indium phosphide (GaInP). In someembodiments, the semiconductor wafer 5 includes an epitaxial layer. Forexample, the semiconductor wafer 5 has an epitaxial layer overlying abulk semiconductor. In some other embodiments, the semiconductor wafer 5may be a silicon-on-insulator (SOI) or a germanium-on-insulator (GOI)substrate.

The semiconductor wafer 5 may have various device elements. Examples ofdevice elements that are formed in the semiconductor wafer 5 includetransistors (e.g., metal oxide semiconductor field effect transistors(MOSFET), complementary metal oxide semiconductor (CMOS) transistors,bipolar junction transistors (BJT), high voltage transistors,high-frequency transistors, p-channel and/or n-channel field-effecttransistors (PFETs/NFETs), etc.), diodes, and/or other applicableelements. Various processes are performed to form the device elements,such as deposition, etching, implantation, photolithography, annealing,and/or other suitable processes. In some embodiments, a shallow trenchisolation (STI) layer, an inter-layer dielectric (ILD), or aninter-metal dielectric layer covers the device elements formed on thesemiconductor wafer 5.

The CMP module 10 is configured for performing a planarization processon a semiconductor wafer 5 in a semiconductor manufacturing process. Insome embodiments, the CMP module 10 includes a base 110, a number ofpolishing pads 120 a, 120 b, and 120 c, a number of load cups 130, and ahead rotation unit 140. The elements of the CMP module 10 can be addedto or omitted, and the disclosure should not be limited by theembodiments.

In some embodiments, the polishing pads 120 a, 120 b, and 120 c areprovided on the base 110. The three polishing pads 120 a, 120 b and 120c facilitate simultaneous processing of multiple wafers in a short time.Each of the polishing pads is mounted on a rotatable carousel (not shownin the figures). Pad conditioners 121 a, 121 b and 121 c are provided onthe base 100 and can be swept over the respective polishing pads 120 a,120 b and 120 c for conditioning of the polishing pads 120 a, 120 b and120 c. Slurry supply arms 122 a, 122 b and 122 c are further provided onthe base 110 for supplying slurry to the surfaces of the respectivepolishing pads 120 a, 120 b and 120 c.

The load cups 130 are configured for the loading and unloading ofsemiconductor wafers 5. In some embodiments, each the load cup 130includes a circular pedestal on which the semiconductor wafer 5 isplaced for loading the semiconductor wafer 5 onto the polishing pads 120a, 120 b and 120 c, and for unloading the semiconductor wafer 5 from thepolishing pad 120 a, 120 b and 120 c.

The head rotation unit 140 has a number of polishing heads 141 a, 141 b,141 c, and 141 d for holding and fixedly rotating the semiconductorwafers 5 on the polishing pads 120 a, 120 b and 120 c. The polishingheads 141 a, 141 b, 141 c, and 141 d of the head rotation unit 140 aremounted on respective rotation shafts (not shown in the figures) whichare rotated by a driving mechanism inside the head rotation unit 140.The polishing heads 141 a, 141 b, 141 c, and 141 d hold respectivesemiconductor wafers 5 and press the semiconductor wafers 5 against thetop surfaces of the respective polishing pads 120 a, 120 b and 120 c. Inthis manner, material layers are removed from the respectivesemiconductor wafers 5.

The rinse station module 20 includes a container 21 in accordance withsome embodiments. The container 21 is configured for submerging asemiconductor wafer 5 within a cleaning fluid contained therein. In someembodiments, the rinse station module 20 may include a transducer (notshown in the figures) mounted to the bottom of the container 21. Thetransducer is used to direct sonic energy upward to the semiconductorwafer 5. Thus, sonic energy from the transducer is directed verticallytoward to the semiconductor wafer 5. As a result, the semiconductorwafer 5 is impacted by equal amounts of sonic energy during each fullrevolution of the semiconductor wafers 5.

The first cleaning module 30 is arranged adjacent to the rinse station20 and is configured to receive the semiconductor wafer 5 which has beencleaned by the rinse station 20. In some embodiments, as shown in FIG.2, the first cleaning module 30 includes a cleaning tank 31, a cleaningbrush assembly 32, and a liquid agitation assembly 33.

In some embodiments, the cleaning brush assembly 32 includes tworotation shafts 321 and two brush members 322. One of the rotationshafts 321 extends along a rotation axis C1 and is rotatable about thecorresponding rotation axis C1. The other rotation shaft 321 extendsalong a rotation axis C2 and is rotatable about the correspondingrotation axis C2. In some embodiments, the rotation axes C1 and C2 areparallel to a vertical direction. A main fluid path 323 is formed ineach of the rotation shafts 321. In addition, a number of holes 324 areformed on an outer wall of each of the rotation shafts 321 and fluidlyconnects to the main flow path 323. In some embodiments, the tworotation shafts 321 are arranged in a movable manner such that thedistance between the two rotation shafts 321 is adjustable.

The two brush members 322 respectively connect to the two rotationshafts 321. Each of the two brush members 322, for example, includes asponge. In some embodiments, each of the brush members 322circumferentially surrounds the corresponding rotation shafts 321 andcovers the holes 324 formed on the outer wall of the rotation shaft 321.As shown in FIG. 1, two ends of each of the rotation shafts 321 are notcovered by the brush members 322. The rotation shaft 321 may be held bya cap which is configured to drive the rotation shaft 321 to rotate.

The liquid agitation assembly 33 includes two agitation transducers 331,and a signal generator 332 electrically connected to the agitationtransducers 331, in accordance with some embodiments. In someembodiments, the two agitation transducers 331 are respectivelyconnected to the two rotation shafts 321. Each of the two agitationtransducers 331 may circumferentially surround a segment of thecorresponding rotation shafts 321 which is not covered by the brushmember 322. In some embodiments, during operation, an alternatingvoltage from the signal generator 332 is applied to the agitationtransducers 331 resulting in transducer oscillation between compressionand expansion thereby coupling megasonic energy to the fluid passingthrough the rotation shafts 321.

In some embodiments, the first cleaning module 30 further includes twowafer supports (not shown in figures). The two wafer supports areconfigured to vertically support the semiconductor wafer 5. The twosupports are rotatable, and each preferably comprises a rotatable wheelhaving a v-shaped groove for supporting the semiconductor wafer 5 withminimal contact. A motor may be coupled to the two supports to drive thetwo supports to actively rotate. Therefore, the two supports act as arotating mechanism for causing the semiconductor wafer 5 to rotate.However, it should be appreciated that many variations and modificationscan be made to embodiments of the disclosure.

It is appreciated that the configuration of the first cleaning module 30should not be limited to the embodiments mentioned above, and the liquidagitation assembly 33 can be modified as long as the agitated liquid canbe applied on the brush member 322.

FIG. 3 shows a schematic view of a first cleaning module 30 a, inaccordance with some embodiments. In some embodiments, differencesbetween the first cleaning module 30 a and the first cleaning module 30shown in FIG. 2 include the two agitation transducers 331 a of a liquidagitation assembly 33 a being positioned on the side panel 311 of thecleaning tank 31. In some embodiments, a number of side walls define aspace for cleaning the semiconductor wafer 5, and the two agitationtransducers 331 a are positioned on different side walls of the cleaningtank 31.

In some embodiments, the two agitation transducers 331 a is fluidlyconnected to a cleaning liquid source and is configured to agitate acleaning liquid from the cleaning liquid source to clean the brushmember 322. The two agitation transducers 331 a may apply the agitatedcleaning liquid on the outer surface of the brush member 322 at an angleranging from about 0 degrees to about 180 degrees relative to thevertical direction parallel to the rotation axis C1 of the cleaningbrush assembly 32. With the agitated cleaning liquid supplied by the twoagitation transducers 331 a, the contaminated particles accumulated inthe brush member 322 are removed.

FIG. 4 shows a schematic view of a first cleaning module 30 b, inaccordance with some embodiments. In some embodiments, differencesbetween the first cleaning module 30 b and the first cleaning module 30shown in FIG. 2 include the two agitation transducers 331 b of a liquidagitation assembly 33 a being positioned on the side panel 311 of thecleaning tank 31 and extending for a predetermined length that isgreater than the diameter of the semiconductor wafer 5.

In some embodiments, the two agitation transducers 331 b is fluidlyconnected to a cleaning liquid source and is configured to agitate acleaning liquid from the cleaning liquid source to clean the brushmember 322. The two agitation transducers 331 b may be equal in lengthto the brush member 322 in a vertical direction parallel to the rotationaxis C1. Alternatively, each of the two agitation transducers 331 b hasa length that is greater than that of the brush member 322 in thevertical direction. With the agitated cleaning liquid supplied by thetwo agitation transducers 331 b, the entire outer surface of each of thebrush members 322 is sufficiently cleaned during the rotation of thebrush members 322.

In some embodiments, the two agitation transducers 331 b and the tworotation shafts are arranged along a straight line. In some embodiments,the two agitation transducers 331 b and the two rotation shafts are notarranged along a straight line. The two agitation transducers 331 b mayoffset with an imaginary line connecting between the two rotation shafts321.

Referring to FIG. 1, the second cleaning module 40 is arranged adjacentto the first cleaning module 30 and is configured to receive thesemiconductor wafer 5 which has been cleaned by the first cleaningmodule 30. The second cleaning module 40 may be the same or differentfrom the first cleaning module 30. For example, the first cleaningmodule 30 has a configuration as shown in FIG. 2, and the secondcleaning module 40 has a configuration as shown in FIG. 3. In addition,the cleaning liquid supplied to the first cleaning module 30 may be thesame or different from that supplied to the second cleaning module 40.Moreover, the agitated cleaning liquid in different cleaning modules maybe agitated at the same or different frequency, so as to enhancecleaning efficiency.

The SRD module 50 is arranged adjacent to the second cleaning module 40and is configured to receive the semiconductor wafer 5 which has beencleaned by the second cleaning module 40. When the semiconductor wafer 5is transferred to the SRD module 50, the semiconductor wafer 5 is rinsedwith deionized water and then dried.

The transferring module 60 includes one or more driving elements (notshown in figures) and a number of robot arms 61, in accordance with someembodiments. The driving element, such as a motor, is controlled by acontrol module and is coupled to the robot arms 61. The robot arms 61are driven by the driving element to provide both radial and rotationalmovement in a fixed plane to pick up, transfer, and deliver thesemiconductor wafer 5 from one location within the CMP system 1 toanother. For example, with the transferring module 60, the semiconductorwafer 5 is transferred between a carrier 65, such as a FOUP, and the CMPmodule 10. Alternatively, the semiconductor wafer 5 is transferredbetween the CMP module 10 and the rinse station 60 by the transferringmodule 60. Alternatively, the semiconductor wafer 5 is transferredbetween the SRD module 50 and the carrier 65.

FIG. 5 is a flow chart illustrating a method 70 for cleaning a wafer, inaccordance with some embodiments. For illustration, the flow chart willbe described with the schematic views shown in FIGS. 1 and 2. Some ofthe stages described can be replaced or eliminated for differentembodiments. Additional features can be added in the semiconductordevice structure. Some of the features described below can be replacedor eliminated for different embodiments.

The method 70 begins with an operation 71 in which one or moresemiconductor wafer (such as semiconductor wafer 5) is provided into aCMP module (such as CMP module 10). In some embodiments, thesemiconductor wafer 5 is transferred into the CMP module 10 by thetransferring module 60 from a carrier 65.

The method 70 continues with operation 72, in which the semiconductorwafer 5 is polished by at least one polishing pad (such as polishingpads 120 a, 120 b, 120 c) of the CMP module 10. Each polishing padrepresents a separate polishing step in which a different material onthe wafer may be polished. For example, the first polishing step on thefirst polishing pad 120 a may be a copper polishing step; the secondpolishing step on the second polishing pad 120 b may be a tantalumnitride (TaN) polishing step; and the third polishing step on the thirdpolishing pad 120 c may be an oxide polishing step. However, it shouldbe appreciated that many variations and modifications can be made toembodiments of the disclosure.

The method 70 continues with operation 73, in which the semiconductorwafer 5 is removed from the CMP module 10. In some embodiments, thesemiconductor wafer 5 is removed from the CMP module 10 by thetransferring module 60 and transferred to the rinse station module 20 orthe first cleaning modules 30 to clean or remove polishing residue afterchemical mechanical polishing.

The method 70 continues with operation 74, in which the semiconductorwafer 5 is cleaned by a cleaning brush assembly (such as cleaning brushassembly 32). In some embodiments, the semiconductor wafer 5 processedby the CMP module 10 is transferred to the first cleaning module 30. Inthe first cleaning module 30, the semiconductor wafer 5 is arrangedvertically and positioned between the two rotation shafts 321. Thedistance between the two rotation shafts 321 may be adjusted after thesemiconductor wafer 5 is positioned therebetween such that contactbetween the two brush members 322 and the semiconductor wafer 5 iscreated.

As shown in FIG. 6A, in some embodiments, the two rotation shafts 321are driven to rotate to clean the front and back surfaces of thesemiconductor wafer 5. In addition, the semiconductor wafer 5 is alsorotated while being cleaned in the first cleaning modules 30. In someembodiments, a cleaning liquid 9, such as deionized water (DIW) orcitric acid, is provided to each brush member 322 via the main fluidpath 323 and the holes 324 of the corresponding rotation shaft 321during the wafer cleaning operation. When the cleaned brush member 322touches the semiconductor wafer 5, which is rotating, particles and/orcontaminants on the semiconductor wafer 5 are removed by the brushmember 322 and the cleaning fluid 221.

However, when the brush member 322 is used to clean the semiconductorwafer(s) for a while, the cleaning efficiency would be reduced due toparticles (or contaminants) accumulating on the brush member 322. FIGS.6A-6C are schematic views of the brush member 322 after being used toclean different wafers, in accordance with some embodiments.

As shown in FIG. 6A, after the semiconductor wafer 5 is cleaned usingthe brush member 322, contaminating particles 7 (or contaminants)accumulate on the brush member 322. As shown in FIG. 6B, after the brushmember 322 is further used to clean more wafers including asemiconductor wafer 5′, more contaminating particles 7 accumulate on thebrush member 322. As the brush member 322 is continually used forcleaning semiconductor wafers, more and more contaminating particles 7may adhere to the brush member 322 and contaminate the brush member 322.Therefore, when the brush member 322 is used to clean a new wafer, someof the particulate contaminants may fall on the new wafer, degrading thecleaning effect of the brush member 322.

For example, as shown in FIG. 6C, after the brush member 322 continuesto be used to clean even more wafers including a semiconductor wafer 5″,even more contaminating particles 7 accumulate on the brush member 322.In some embodiments, some of the contaminating particles 7 fall from thebrush member 322 and are left on the semiconductor wafer 5″. As aresult, the semiconductor wafer 5″ is not sufficiently cleaned, whichwill lead to a yield reduction of the semiconductor wafer 5″.

In order to prevent the problems mentioned above, the method 70continues to an operation 75, in which the cleaning brush assembly 32 iscleaned by using an agitated cleaning liquid. In some embodiments, asshown in FIG. 7, the cleaning liquid 9 applied into the rotation shafts321 is agitated by the liquid agitation assembly 33 and transformed toan agitated cleaning liquid 9′. Afterwards, the agitated cleaning liquid9′ is delivered to the brush member 322 via the main fluid path 323 andthe holes 324 (FIG. 2). Due to the agitated cleaning liquid 9′,contaminating particles 7 adhering to the cleaning brush assembly 32 areshaken away from the brush assembly 32. As a result, the cleaning brushassembly 32 is ready for being used for cleaning another semiconductorwafer 5 which has been polished.

In some embodiments, the brush member 322 is washed by the agitatedcleaning liquid 9′ applied from the agitation transducers 331 c or 331 bas shown in FIGS. 3 and 4. In addition, a clean liquid is simultaneouslysupplied into the rotation shaft of the cleaning brush assembly 32 torinse the brush member 322. Alternatively, there is no clean liquidbeing supplied into the rotation shaft of the cleaning brush assembly 32during the supply of the agitated cleaning liquid 9′ from the agitationtransducers 331 c or 331 b.

In some embodiments, since the semiconductor wafer 5 is washed by thebrush member 322 which is cleaned by the agitated cleaning liquid 9′while the wafer cleaning process, cleaning process of the embodimentstakes less time than the conventional cleaning process. As a result, andan overall throughput of the CMP system 1 is increased. In someembodiments, the time period for performing the operation of cleaningthe semiconductor wafer 5 by rotating a cleaning brush assembly 32ranges from about 20 seconds to about 80 seconds.

In some embodiments, the liquid agitation assembly 33 is operated whilethe semiconductor wafer 5 is cleaned by the brush member 322. Slurry orresidue on the semiconductor wafer 5 is also cleaned by the agitatedcleaning liquid 9′. Alternatively or additionally, the liquid agitationassembly 33 is operated after the removal of the semiconductor wafer 5from the brush member 322. Alternatively or additionally, the liquidagitation assembly 33 is kept in operation regardless of the existenceor absence of the semiconductor wafer 5 in the first cleaning module 30.In some embodiments, the agitated cleaning liquid 9′ with thecontaminating particles 7 is drained away through a liquid outlet unit(not shown in figures) connected to the cleaning tank 31. Thecontaminated cleaning liquid is not kept in the cleaning tank 31.

In some embodiments, the liquid agitation assembly 33 is capable ofagitating the cleaning fluid at a frequency in a range from about 500KHz to about 2.5 MHz. The frequency of oscillation may be variedaccording to the particle size accumulated in the brush assembly 32. Forexample, if the particles accumulated in the brush assembly 32 have arelatively large size, the cleaning liquid is oscillated at a lowfrequency, so that the cleaning efficiency is enhanced. However, itshould be appreciated that many variations and modifications can be madeto embodiments of the disclosure.

In some embodiments, after the semiconductor wafer 5 is cleaned by thefirst cleaning module 30, the semiconductor wafer 5 is transferred tothe second cleaning module 40 to be cleaned again. Similar to thecleaning process performed in the first cleaning module 30, the brushmember 322 in the second cleaning module 40 is also cleaned by using anagitated cleaning liquid.

In some embodiments, after the semiconductor wafer 5 is cleaned by thefirst cleaning module 30 or the second cleaning module 40, thesemiconductor wafer 5 is transferred to the SRD module 50. When thesemiconductor wafer 5 is transferred to the SRD module 50, thesemiconductor wafer 5 is rinsed with deionized water and then driedbefore being transferred to the carrier 65.

FIG. 8 illustrates a Chemical Mechanical Polishing (CMP) system 1 c forprocessing a semiconductor wafer 5, in accordance with some embodiments.The CMP system 1 c includes a CMP module 10 c, a rinse station module 20c, a number of cleaning modules, such as the cleaning modules 30 c, 40c, and 80 c, a spin-rinse-dry (SRD) module 50 c, and a number oftransferring modules 60 c. The elements of the CMP system 1 c can beadded to or omitted, and the disclosure should not be limited by theembodiments.

The CMP module 10 c is configured for performing a planarization processof a semiconductor wafer 5 in semiconductor manufacturing process. Insome embodiments, the CMP module 10 c includes a number of polishingstations 11 c. Each polishing station 11 c includes a first polishingapparatus 111 c and second polishing apparatus 112 c. Any number ofpolishing stations 11 c is possible. Each polishing station 11 c isconfigured to provide a first polishing operation and a second polishingoperation to a number of semiconductor wafers 5.

In some embodiments, the first polishing operation and the secondpolishing operation differ by type and chemistry of a polishing slurryused, and process recipe such as spin rate, force applied to thesemiconductor wafers 5, and duration of the polish. In some embodiments,the first polishing operation may be a rough polish and the secondpolishing operation may be a fine polish. In some embodiments, the firstpolishing operation may be configured to remove dielectric material fromthe semiconductor wafers 5 and the second polishing operation may beconfigured to remove metal.

The rinse station module 20 c is configured for submerging asemiconductor wafer 5 within a cleaning fluid contained therein. Thefirst cleaning module 30 c is arranged adjacent to the rinse stationmodule 20 c and is configured to receive the semiconductor wafer 5 whichhas been cleaned by the rinse station 20 c.

As shown in FIG. 9, the first cleaning module 30 c includes a cleaningtank 31 c, a cleaning brush assembly 32 c, and a liquid agitationassembly 33 c, in accordance with some embodiments. In some embodiments,the cleaning brush assembly 32 c includes two rotation shafts 321 c andtwo brush members 322 c. One of the rotation shafts 321 c extends alonga rotation axis C3 and is rotatable about the corresponding rotationaxis C3. The other rotation shaft 321 c extends along a rotation axis C4and is rotatable about the corresponding rotation axis C4. In someembodiments, the rotation axes C3 and C4 are parallel to a horizontaldirection. The configurations of the rotation shafts 321 c and the brushmembers 322 c may be similar to the rotation shaft 321 and the brushmembers 322 as shown in FIG. 2, and are not described in detail forbrevity. However, it should be appreciated that many variations andmodifications can be made to embodiments of the disclosure.

The liquid agitation assembly 33 c includes two agitation transducers331 c, and a signal generator 332 c electrically connected to theagitation transducers 331 c, in accordance with some embodiments. Insome embodiments, the two agitation transducers 331 c are respectivelyconnected to the two rotation shafts 321 c of the cleaning brushassembly 32 c. In some embodiments, during operation, an alternatingvoltage from the signal generator 332 c is applied to the agitationtransducers 331 c resulting in transducer oscillation betweencompression and expansion thereby coupling megasonic energy to the fluidpassing through the rotation shafts 321 c.

It is appreciated that the configuration of the first cleaning module 30c should not be limited to the embodiments mentioned above, and theliquid agitation assembly 33 c can be modified as long as the agitatedliquid can be applied on the brush member 322 c.

FIG. 10 shows a schematic view of a first cleaning module 30 d, inaccordance with some embodiments. In some embodiments, differencesbetween the first cleaning module 30 d and the first cleaning module 30c shown in FIG. 9 include the two agitation transducers 331 d beingpositioned on the side panel 311 c of the cleaning tank 31 c.

In some embodiments, the two agitation transducers 331 d is fluidlyconnected to a cleaning liquid source and is configured to agitate acleaning liquid from the cleaning liquid source to clean the brushmember 322 c. In some embodiments, the two agitation transducers 331 dapplies the agitated cleaning liquid toward an outer surface of thebrush member 322 c by an angle raging from about 0 degree to about 180degrees relative to a horizontal direction. The horizontal direction isparallel to the rotation axes C3 and C4 of the cleaning brush assembly32 c.

FIG. 11 shows a schematic view of a first cleaning module 30 e, inaccordance with some embodiments. In some embodiments, differencesbetween the first cleaning module 30 e and the first cleaning module 30c shown in FIG. 9 include the two agitation transducers 331 e of aliquid agitation assembly 33 e being positioned on the side panel 311 cof the cleaning tank 31 c and extending for a predetermined lengthlarger than the diameter of the semiconductor wafer 5.

In some embodiments, the two agitation transducers 331 e is fluidlyconnected to a cleaning liquid source and is configured to agitate acleaning liquid from the cleaning liquid source to clean the brushmember 322 c. The two agitation transducers 331 e may be equal in lengthto the brush member 322 c in a horizontal direction parallel to therotation axes C3 and C4 of the cleaning brush assembly 32 c.Alternatively, each of the two agitation transducers 331 e has a lengthlarger than that of the brush member 322 c in the horizontal direction.With the agitated cleaning liquid supplied by the two agitationtransducers 331 e, the entire outer surface of each of the brush members322 c is sufficiently cleaned during the rotation of the brush members322 c.

The second cleaning module 40 c is arranged adjacent to the firstcleaning module 30 c and is configured to receive the semiconductorwafer 5 which has been cleaned by the first cleaning module 30 c. Thethird cleaning module 80 c is arranged adjacent to the second cleaningmodule 40 c and is configured to receive the semiconductor wafer 5 whichhas been cleaned by the second cleaning module 40 c.

It is appreciated that the second cleaning module 40 c and the thirdcleaning module 80 c may have a configuration similar to the variousconfigurations of the first core 30 c, 30 d, and 30 e disclosed above.In addition, the cleaning liquid supplied to the three cleaning modulesmay be the same or different. Moreover, the agitated cleaning liquid inthe three cleaning modules may be agitated at the same or differentfrequency, so as to enhance cleaning efficiency.

Embodiments of mechanisms for cleaning a brush member in a post-CMPapparatus described above apply an agitated cleaning liquid on the brushmember. Due to the assistance of the agitation energy, the brush memberis cleaned efficiently. As a result, a yield reduction of thesemiconductor wafer due to contamination is prevented. In addition,since the brush member is reused to clean other wafers, the time periodfor shutting off the cleaning system for replacing a new brush membercan be prolonged, and fabrication cost and time are reduced.

In accordance with some embodiments, a method for processing asemiconductor wafer is provided. The method includes providing thesemiconductor wafer into a Chemical Mechanical Polishing (CMP) module.The method further includes polishing the semiconductor wafer. Themethod also includes removing the semiconductor wafer from the CMPmodule. In addition, the method includes cleaning the semiconductorwafer by a cleaning brush assembly. Additionally, the method includescleaning the cleaning brush assembly by using an agitated cleaningliquid.

In accordance with some embodiments, a method for cleaning asemiconductor wafer after a Chemical Mechanical Polishing (CMP) processis provided. The method includes providing the semiconductor wafer intoa cleaning module. The method further includes cleaning thesemiconductor wafer by rotating a cleaning brush assembly. The methodalso includes applying an agitated cleaning liquid to clean the cleaningbrush assembly.

In accordance with some embodiments, a system for cleaning a wafer insemiconductor fabrication is provided. The system includes a ChemicalMechanical Polishing (CMP) module used to polish a semiconductor wafer.The system further includes a cleaning brush assembly. The cleaningbrush assembly is used to clean the semiconductor wafer. The system alsoincludes a liquid agitation assembly. The liquid agitation assembly isused to produce an agitated cleaning liquid to clean the cleaning brushassembly.

Although the embodiments and their advantages have been described indetail, it should be understood that various changes, substitutions, andalterations can be made herein without departing from the spirit andscope of the embodiments as defined by the appended claims. Moreover,the scope of the present application is not intended to be limited tothe particular embodiments of the process, machine, manufacture,composition of matter, means, methods, and steps described in thespecification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps. In addition, each claim constitutes a separateembodiment, and the combination of various claims and embodiments arewithin the scope of the disclosure.

1. A method for processing a semiconductor wafer, comprising: providingthe semiconductor wafer into a Chemical Mechanical Polishing (CMP)module; polishing the semiconductor wafer; removing the semiconductorwafer from the CMP module; cleaning the semiconductor wafer by a brushmember surrounding a rotation shaft; supplying a cleaning liquid to anagitation transducer and agitating the cleaning liquid to an agitatedcleaning liquid by the agitation transducer; supplying the agitatedcleaning liquid along a predetermined path, wherein at least a sectionof the predetermined path is parallel to a rotation axis about which therotation shaft rotates; and cleaning the brush member by using theagitated cleaning liquid.
 2. The method as claimed in claim 1, whereinthe section of the predetermined path comprises a main flow path that isformed in the rotation shaft and extends along the rotation shaft, andthe predetermined path terminates at an inner surface of the brushmember that is in contact with the rotation shaft.
 3. (canceled) 4.(canceled)
 5. The method as claimed in claim 1, wherein the operation ofcleaning the brush member by using the agitated cleaning liquid isperformed when the semiconductor wafer is cleaned by the brush member oris performed after the removal of the semiconductor wafer.
 6. The methodas claimed in claim 1, wherein the operation of cleaning thesemiconductor wafer by the brush member is performed for a time periodranging from about 20 seconds to about 80 seconds.
 7. The method asclaimed in claim 1, wherein the agitated cleaning liquid is agitated ata frequency in a range from about 500 KHz to about 2.5 MHz by theagitation transducer.
 8. A method for cleaning a semiconductor waferafter a Chemical Mechanical Polishing (CMP) process, comprising:providing the semiconductor wafer into a cleaning module; cleaning thesemiconductor wafer by rotating a brush member surrounding a rotationshaft; and supplying a cleaning liquid to an agitation transducer andagitating the cleaning liquid to an agitated cleaning liquid by theagitation transducer; and supplying the agitated cleaning liquid along apredetermined path to clean the brush member, wherein at least a sectionof the predetermined path is parallel to a rotation axis about which therotation shaft rotates.
 9. The method as claimed in claim 8, wherein thesection of the predetermined path comprises a main flow path that isformed in the rotation shaft and extends along the rotation shaft, andthe predetermined path terminates at an inner surface of the brushmember that is in contact with the rotation shaft.
 10. (canceled) 11.(canceled)
 12. The method as claimed in claim 8, wherein the operationof applying the agitated cleaning liquid to clean the brush member isperformed when the semiconductor wafer is cleaned by the brush member oris performed after the removal of the semiconductor wafer.
 13. Themethod as claimed in claim 8, wherein the operation of cleaning thesemiconductor wafer by rotating the brush member is performed for a timeperiod ranging from about 20 seconds to about 80 seconds.
 14. The methodas claimed in claim 8, wherein the agitated cleaning liquid is agitatedat a frequency in a range from about 500 KHz to about 2.5 MHz by theagitation transducer. 15-20. (canceled)
 21. The method as claimed inclaim 1, wherein the section of the predetermined path is formed in theagitation transducer that is separated from the brush member andextended along the rotation axis.
 22. The method as claimed in claim 1,wherein the agitation transducer circumferentially surrounds a segmentof the rotation shaft which is not covered by the brush member.
 23. Themethod as claimed in claim 1, wherein the predetermined path extendsacross a gap between the brush member and the agitation transducer andterminates at an outer surface of the brush member that is adapted forcleaning the semiconductor wafer.
 24. The method as claimed in claim 8,wherein the section of the predetermined path is formed in the agitationtransducer that is separated from the brush member and extended alongthe rotation axis.
 25. The method as claimed in claim 8, wherein theagitation transducer circumferentially surrounds a segment of therotation shaft which is not covered by the brush member.
 26. The methodas claimed in claim 8, wherein the predetermined path extends across agap between the brush member and the agitation transducer and terminatesat an outer surface of the brush member that is adapted for cleaning thesemiconductor wafer.
 27. A method for processing a semiconductor wafer,comprising: providing the semiconductor wafer into a Chemical MechanicalPolishing (CMP) module; polishing the semiconductor wafer; removing thesemiconductor wafer from the CMP module; cleaning the semiconductorwafer by a cleaning brush assembly; supplying a cleaning liquid to anagitation transducer that is separated from the cleaning brush assemblyand agitating the cleaning liquid to an agitated cleaning liquid by theagitation transducer; and cleaning an outer surface of the cleaningbrush assembly by using the agitated cleaning liquid.
 28. The method asclaimed in claim 27, wherein applying the agitated cleaning liquid toclean the cleaning brush assembly comprises applying the agitatedcleaning liquid toward the outer surface of a brush member of thecleaning brush assembly at an angle ranging from about 0 degrees toabout 180 degrees relative to a rotation axis about which the cleaningbrush assembly rotates.
 29. The method as claimed in claim 27, whereinthe operation of cleaning the semiconductor wafer by the cleaning brushassembly is performed for a time period ranging from about 20 seconds toabout 80 seconds.
 30. The method as claimed in claim 27, wherein theagitated cleaning liquid is agitated at a frequency in a range fromabout 500 KHz to about 2.5 MHz by the agitation transducer.